The best way I have found to lower the humidity without a de-humidifier is with some sort of extraction fan. I don't know what your set up is like but if your growing in a tent or box or even a room but I had the high humidity problem when I started growing in a tent. I got a 4 inch in-line fan and placed it inside the tent and it pulls hot, humid, and stale air out. I have a small screen at the base of my tent that lets fresh air in